Patent Application
20110225995
The field of the invention relates generally to improving refrigeration efficiency and more particularly to defrosting and clearing debris from a refrigeration component using a pressurized dry gas, such as air.
In conventional refrigeration systems, a refrigerant in vapor form is heated at a compressor. The heated vapor is circulated from the compressor to a condenser, which cools the heated vapor into a liquid. The liquid refrigerant is circulated to an evaporator, where the liquid expands and cools. Typically, a fan draws air through tubing and fins of the evaporator thereby cooling the air. This cooled air may be used to refrigerate or otherwise lower the temperature of ambient air. Using these systems, frozen foods or other items may be refrigerated in an enclosure such as a freezer.
However, one problem with conventional refrigeration systems is that frost and/or debris carried by the air drawn through the tubing and fins of the evaporator oftentimes builds up on the outside surfaces of the evaporator, including the tubing and fins. The frost and/or debris causes blocking air flow, which reduces efficiency of these conventional refrigeration systems. Conventional systems address this problem by defrosting the evaporator.
One method of defrosting the evaporator includes operating a freezer in a defrost cycle or operation. An example defrost cycle circulates hot gas refrigerant from the compressor to the evaporator (instead of to the condenser as occurs during normal operation) in order to melt frost that forms on the outside surfaces of the evaporator during normal operation. Such a method is described in U.S. Pat. No. 4,736,594 to Pao, entitled “Method and apparatus for controlling refrigeration systems,” which is incorporated by reference in its entirety. During both normal and defrost operation, the hot gas from the compressor first passes through a water drain pan and through a coil tubing and fins and the defrost water is drained to the outside of the freezer as defrost water during the defrost cycle. Such a system is shown in the American Society of Heat & Refrigeration Engineering (ASHRAE) System Manual, Chapter 27.14: Liquid Recirculation and Evaporator Piping, which is incorporated by reference in its entirety. Another method for defrosting the evaporator includes using electric heating elements that heat the evaporator.
These and other conventional methods of defrosting an evaporator involve periodically shutting down the refrigeration system in order to defrost the evaporator, wasting time and energy during the defrosting cycle. When such systems are used for frozen food processing, for example, such a shutdown increases food processing time and cost.
These and other drawbacks exist.
What is needed is an efficient method of defrosting a refrigeration component such as an evaporator, while reducing or eliminating defrosting cycles and maintaining refrigeration efficiency without shutting down refrigeration systems.
The invention addressing these and other drawbacks of conventional refrigeration system relates to systems, apparatuses and methods that defrost and/or clear debris from a refrigeration component such as an evaporator. For example, a cleaning apparatus for defrosting and/or clearing debris from the refrigeration component uses a pressurized gas, such as air. The cleaning apparatus may include an air compressor. The air compressor may pressurize the air. The pressurized air may be filtered to remove moisture and/or other contaminants to thereby generate pressurized dry air from the air compressor. The apparatus may include a reservoir coupled to the air compressor. The reservoir may receive and store the pressurized dry air from the air compressor. The reservoir may be coupled to one or more air distribution manifolds coupled to the reservoir. Each of the one or more air distribution manifolds may be coupled to an air discharge component such as an air pipe or tube. The air discharge component may receive the pressurized air from the air exhaust and may discharge the pressurized air through a plurality of orifices to the refrigeration component thereby cleaning the refrigeration component without interrupting operation of the refrigeration component.
In some implementations of the invention, the cleaning apparatus may be integrated with the refrigeration component. For example, the air discharge component may include one or more tubes that have orifices through which pressurized air is discharge. The one or more tubes may be integrated with or otherwise alongside one or more tubes of an evaporator.
In some implementations of the invention, the cleaning apparatus may be removably coupled to the refrigeration component. For example, the air discharge component may be housed in a portable cleaning apparatus that is placed nearby the refrigeration component or other target to be defrosted or cleared of debris. The portable cleaning apparatus may be removed and placed nearby another refrigeration component to be defrosted or cleared of debris.
Various other objects, features, and advantages of the invention will be apparent through the detailed description of the preferred embodiments and the drawings attached hereto. It is also to be understood that both the foregoing general description and the following detailed description are exemplary and not restrictive of the scope of the invention.
According to various implementations of the invention, refrigeration subsystem 110 may include, among other things, a compressor 112, a condenser 114, an evaporator 116, a heat exchange component 118, and a fan 119. Refrigeration subsystem 110 may pass a refrigerant 101 as a hot gas to condenser 114, where refrigerant 101 may cool to a liquid. The liquid may be passed from condenser 114 to evaporator 116. Evaporator 116 includes heat exchange component 118, where heat from ambient air may be exchanged or otherwise transferred to heat exchange component 118. Heat exchange component 118 may include, for example, one or more heat exchange tubes through which refrigerant 101 is circulated, heat exchange plates, or other structure for heat exchange. In some implementations, heat exchange component 118 may include a tube and fin design as known in the art. Fan 119 may circulate the heat-exchanged (refrigerated) air from evaporator 116, thereby providing the refrigerated air. As would be appreciated “evaporator” 116 may be any component or subsystem where heat exchange for refrigeration takes place.
During operation of refrigeration subsystem 110, frost or other debris may build up around heat exchange component 118 or other portion of evaporator 116. According to various implementations of the invention, defrosting apparatus 120 cleans heat exchange component 118 by discharging pressurized air 138 (illustrated in
According to various implementations of the invention, defrosting apparatus 120 may include, among other things, an air compressor 122, a filter 124, a reservoir 126, a control valve 128, a processor 130, an air distribution manifold 132 and a plurality of air discharge components 134 (illustrated in
In some implementations, control valve 128 may be coupled to reservoir 126 and to air distribution manifold 132. In these implementations, control valve 128 may control delivery of pressurized air 138 from reservoir 126 to air distribution manifold 132. For example, control valve 128 may include a solenoid valve that when in a closed state prevents pressurized air 138 from entering air distribution manifold 132. When in an open state, control valve 128 may cause pressurized air 138 to enter air distribution manifold 132. In some implementations, control valve 128 may open then rapidly close a valve gate (not illustrated in
In some implementations, control valve 128 may be communicably coupled to processor 130, which may include a programmed logic controller and/or other circuitry or logic that controls opening and closing of control valve 128. In some implementations, processor 130 may be programmed with or otherwise execute instructions to cause defrosting apparatus 120 to clean refrigeration subsystem 110 at different times. In some implementations, processor 130 may cause control valve 128 to discharge pressurized air 138 upon receipt of a command to initiate cleaning. In some implementations, the command may originate from a user operating a user interface, a sensor that senses a level of frost and/or debris build-up on refrigeration subsystem 110 (user interface and sensor not illustrated in
According to various implementations of the invention, air distribution manifold 132 may be coupled to air discharge components 134. Air discharge components 134 may be any size, shape, or configuration through which pressurized air 138 may flow from air distribution manifold 132 as appropriate. For example, air discharge components 134 may include tubular (pipe-like structures), planar sheets, or other shape and/or configuration. Although illustrated in
According to various implementations of the invention, orifices 136 may include or be formed from an opening in air discharge components 134; a nozzle; or other structure through which pressurized air 138 is discharged from air discharge components 134. Orifices 136 may be any size or shape suitable to discharge pressurized air 138.
According to various implementations of the invention, orifices 136 may be collectively configured in any geometric pattern. In other words, two or more orifices 136 may be positioned with respect to one another to provide a particular spray pattern to discharge pressurized air 138. In some implementations, orifices 136 may be positioned along air discharge components 134 to achieve the particular spray pattern. In some implementations, an angular discharge of each of orifices 136 may be oriented to achieve the particular spray pattern. The “angular discharge” refers to the direction in which pressurized air 138 is discharged from an orifice 136 to a target, such as heat exchange component 118. Thus, by positioning orifices 136 and/or adjusting the angular discharge of orifices 136, various spray patterns may be achieved. In some implementations, varying the position and/or angular discharge of orifices 136 provides flexibility in placement of air discharge components 134 relative to heat exchange component 118.
In operation, air compressor 122 may generate pressurized air 138. Before or after compressing, air filter 124 may filter the air, thereby providing pressurized dry air, which is stored in reservoir 126. Processor 130 may provide an indication 131 to control valve 128. In response to indication 131, control valve 128 rapidly opens and re-closes a valve to thereby cause pressurized dry air to enter air distribution manifold 132 and air discharge component 134. Air discharge component 134 discharges the pressurized dry air 138 through a plurality of orifices 136 to thereby clean heat exchange component 118.
Although not illustrated in
Although illustrated in
As used herein to describe various components and implementations of the invention, “air” may include ambient air as well other gas or combination of gases suitable for use with the various components and implementations described. For example, implementations of “air” manifolds described herein may be “gas” manifolds. Furthermore, various implementations of air/gas manifolds may use compressed gasses other than air compressed from ambient air that is suitable to be discharged through orifices described herein. In some implementations, for example, various air/gas manifolds described herein may be removably or fixedly coupled to a pressurized gas container storing a compressed or pressurized gas.
In some implementations, orifices 136 may be positioned to direct pressurized air 202 toward a target. The target may be, for example, heat exchange component 118 illustrated in
It should be noted that the particular configuration (i.e., positions and orientations) of orifices 136 and number of air discharge components 134 illustrated in
In some implementations orifice 136 may be oriented so that the direction of pressurized air 202 has different angular discharges 404 with respect to a hypothetical axis system (illustrated in
In some implementations, as illustrated in
The foregoing example is non-limiting. Orifice 136 in this and other drawing figures may be positioned at different positions so that the hypothetical plane does not intersect the center of air discharge component 134, as would be appreciated.
In some implementations, as illustrated in
In some implementations, as illustrated in
In some implementations, air discharge components 134 may direct pressurized air 202 toward one another for self-cleaning as described above.
In some implementations, as illustrated in
In some implementations, air discharge components 134 may direct pressurized air 202 toward one another for self-cleaning as described above.
In an operation 702, an air compressor may pressurize air. In an operation 704, the air may be filtered and/or dried to remove moisture and/or other contaminants to thereby generate pressurized dry air. In an operation 706, the pressurized dry air may be stored in a storage tank such as a reservoir. In an operation 708, a control valve may receive an indication to rapidly open then re-close. The rapid opening and re-closing of the control valve may cause the pressurized dry air to enter an air distribution manifold and air discharge components coupled thereto. The indication may be received from a processor communicably coupled to the control valve. In other words, the processor may communicate the indication, which may be an electronic control, signal, or other instruction to the control valve. The indication may be generated by the processor in response to programming or other instructions that are executed by the processor. In some implementations, the executed instructions provide commands that cause periodic (i.e., execution at intervals) opening and closing of the control valve. In some implementations, the processor generates the indication in response to a sensor signal from a sensor that indicates that at least a portion of a target such as tubes and fins of a heat exchange component (such as an evaporator) have frost or other debris buildup.
In an operation 710, the pressurized dry air is circulated through the air distribution manifold and air discharge components, where the pressurized dry air is discharged to the target. By discharging the pressurized dry air to the target, thereby defrosting and/or clearing debris from the target.
Other embodiments, uses and advantages of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. The specification should be considered exemplary only, and the scope of the invention is accordingly intended to be limited only by the following claims.
